Steven E. Schwarzbach
Joshua T. Ackerman
Collin A. Eagles-Smith
Michael L. Casazza
Julie L. Yee
Alan C. Heyvaert
David P. Krabbenhoft
Thuy-Vy D. Bui
John Y. Takekawa
2015
Historical methyl mercury in San Francisco Bay
Tabular Digital Data
Sacramento, CA
U.S. Geological Survey
http://dx.doi.org/10.5066/F78P5XKP
San Francisco Bay, California is considered a mercury-impaired watershed. Elevated concentrations of mercury are found in water and sediment as well as fish and estuarine birds. Sources of mercury to the watershed since 1845 include sediment-associated mercury from mercury mining, mercury losses from gold amalgamation activities in mines of the Sierra Nevada, aerial deposition of mercury from global and regional emissions to air, and the direct discharge of mercury to Bay waters associated with the urbanization and industrialization of the estuary. We assessed historical trends in mercury bioaccumulation by measuring mercury concentrations in feathers of the endangered California Ridgway’s rail (formerly California Clapper Rail) using museum specimens. We developed a structural equation model to attribute variation in historical mercury bioaccumulation in rails to sources of mercury, and estimated the toxicological consequences of extreme mercury exposure to rails from known correlations between feather and blood mercury concentrations.
Because of the many historical and contemporary sources of mercury to the Bay, we sought to answer two questions: 1. How has mercury bioaccumulation in the Bay changed over time? And, 2. Can we attribute the observed variation in bioaccumulation over time to different anthropogenic sources of mercury?
1850
2007
Publication date
None planned
-122.567
-109.196
43.328
37.364
None
Mercury
Sediment
Ice Cores
Structural Equation Model
California Ridgway's Rail
Feathers
USGS Metadata Identifier
USGS:558194c3e4b023124e8f0b10
None
Wyoming
San Francisco Bay
Lake Tahoe
None. Please see 'Distribution Info' for details.
None. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations.
U.S. Geological Survey, PACIFIC REGION
Steven E Schwarzbach
Scientist Emeritus
mailing address
Mail Stop 4004, 3020 STATE UNIVERSITY DR. EAST, 3020 State University Drive East
Sacramento
CA
95819
916-203-6466
steven_schwarzbach@usgs.gov
There are four primary contacts for the data contributed to this project.
Josh Ackerman for mercury feather data, jackerman@usgs.gov
David Krabbenhoft for Fremont Glacier data, dpkrabbe@usgs.gov
Alan Heyvaert for Lake Tahoe data Desert Research Institute, Reno Nevada email:alan.heyvaert@dri.edu
Julie Yee for SEM modeling and data transformations. julie_yee@usgs.gov
Others who contributed feathers for mercury analysis include; California Academy of Sciences, UC Davis Wildlife and Fisheries Conservation Biology, San Diego Museum of Natural History, UC Berkeley Museum of Vertebrate Zoology, Fish and wildlife service, San FranciscoBay National Wildlife Refure allowed access to rail carcasses from the 1980 and 1990s.
Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2 (Build 3552) Service Pack N/A (Build N/A)
No formal attribute accuracy tests were conducted.
No formal logical accuracy tests were conducted.
Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
A formal accuracy assessment of the horizontal positional information in the data set has not been conducted.
A formal accuracy assessment of the vertical positional information in the data set has either not been conducted, or is not applicable.
Josh Ackerman
2015
Mercury levels in feathers
Other
Dixon, California
US Geological Survey
Digital and/or Hardcopy Resources
1881
2007
observed
Feathers
Sources: USGS, Museums that contributed feathers (California Academy of Sciences, UC Davis Wildlife and Fisheries Conservation Biology, San Diego Museum of Natural History, UC Berkeley Museum of Vertebrate Zoology,
David Krabbenhoft
2002
Mercury in Fremont Glacier ice cores
Other
journal
David Krabbenhoft
Digital and/or Hardcopy Resources
1849
1993
observed
Fremont Glacier mercury
Data was used as an additional source for input into the model.
Edgar Herbert Bailey and Donald Lough Everhart
1964
New Almanden Mercury mine
Other
Washington D.C.
US Geological Survey
Digital and/or Hardcopy Resources
1850
2007
publication date
Source Input 3
Data was used as an additional source for input into the model.
Hayvaert, A. C.
1998
Lake Tahoe sediment
Other
Davis, Ca
UC Davis
Digital and/or Hardcopy Resources
1828
1990
ground condition
New Almaden Mine
Data was used as an additional source for input into the model.
US Department of the Interior, Bureau of Mines
1965
California Mercury Mining
Other
Washington, D.C.
US Department of the Interior, Bureau of Mines
Digital and/or Hardcopy Resources
1850
1961
observed
California Mercury production
Data was used as an additional source for input into the model.
KC Clarke, S Hoppen, L Gaydos
1997
San Francisco Bay urbanized areas
Other
Moffett Field, CA
US Geological Survey
Digital and/or Hardcopy Resources
1850
1990
publication date
San Francisco Bay urbanized areas
Data was used as an additional source for input into the model.
We aggregated all data to five-year resolution as follows. We first assigned years from 1850 to 2007 into five-year bins by creating year-group identifiers defined by dividing five into each year and rounding down to the nearest integer.
For the two sub-watersheds within the Bay where rail feathers were collected (Central Bay and South Bay), we used SAS statistical software to fit general linear models (GLM) to model variation in mercury concentration in rail feathers based on main effects of year-group, sub-watershed and sex, and an interaction effect between sub-watershed and sex. We used the GLM to derive model-based estimates of mean mercury concentration across both sub-watersheds for each year-group while accounting for sub-watershed and sex differences (also known in SAS as least-squares means). We similarly fit GLM to each sub-watershed separately, based on the main effects of year-group and sex, to calculate model-based estimates of mean mercury concentration for each year-group while accounting for sex differences, for separate sub-watersheds.
For environmental predictors measured at uneven time intervals (1–33 years for mercury deposition in Lake Tahoe sedimentation, 1–8 years for mercury deposition at Fremont glacier, and 12-50 years for San Francisco urbanization area), we filled gaps by linear interpolation in order to develop annual time series. We then averaged these metrics into the same five-year bins used for aggregating the feather concentrations.
The data table consists of all aggregated metrics for mercury concentration in rail feathers and environmental predictors, merged by five-year bins. All metrics are also repeated in standardized form, by dividing by their respective standard deviations taken from the 1880 to 2007 time period when trends in mercury concentration in rail feathers occurred.
2015
Attribute Table
Table containing attribute information associated with the data set.
Producer defined
yeargrp
5-year grouping identifier
Producer defined
370
401
Years
interval
5-year interval
Producer defined
Date range of 5 years
year
middle year of 5-year interval
Producer defined
1852
2006
Year
estimate
model-based estimate of mean Hg concentration, accounting for sex and region differences in sampling
Producer defined
2.88165324705074
43.9718798472944
µg/g dry weight
centralbayest
model-based estimate of mean Hg concentration for Central Bay rails, accounting for sex differences in sampling
Producer defined
4.33003228389398
73.8102446862377
µg/g dry weight
southbayest
model-based estimate of mean Hg concentration for Central Bay rails, accounting for sex differences in sampling
Producer defined
5.17997243660341
49.4603283446466
µg/g dry weight
sfurbanarea
San Francisco urbanized area (interpolated)
Producer defined
0.013834235335625
1.65033544626563
1000 sq km
newalmaden
New Almaden mining Hg production
Producer defined
0
1.08921541891116
kilotons
california
California mining Hg production
Producer defined
0
2.3356775592
kilotons
laketahoedep
Lake Tahoe sediment Hg deposition (interpolated)
Producer defined
5.35964882394383
37.4100731663888
µg/sq m/year
fremontdep
Fremont glacier Hg deposition (interpolated)
Producer defined
1.45328297267477
22.9730031661378
µg/sq m/year
estimate_std
model-based estimate of mean Hg concentration, accounting for sex and region differences in sampling, standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0.271675532309744
4.1455660483787
n/a
centralbayest_std
model-based estimate of mean Hg concentration for Central Bay rails, accounting for sex differences in sampling, standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0.247449393215163
4.21805175185604
n/a
southbayest_std
model-based estimate of mean Hg concentration for South Bay rails, accounting for sex differences in sampling, standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0.366257165069457
3.49716139701955
n/a
sfurbanarea_std
San Francisco urbanized area (interpolated), standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0.0253000703540082
3.01813594212271
n/a
newalmaden_std
New Almaden mining Hg production, standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0
4.83587421047877
n/a
california_std
California mining Hg production, standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0
5.14069285721794
n/a
laketahoedep_std
Lake Tahoe sediment Hg deposition (interpolated), standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0.509585767091614
3.55688244839517
n/a
fremontdep_std
Fremont glacier Hg deposition (interpolated), standardized by dividing by its standard deviation over the 1880-2007 interval
Producer defined
0.246960455527967
3.90386692297983
n/a
The entity and attribute information provided here describes the tabular data associated with the data set. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the data set.
The entity and attribute information was generated by the individual and/or agency identified as the originator of the data set. Please review the rest of the metadata record for additional details and information.
U.S. Geological Survey - ScienceBase
mailing address
Denver Federal Center
Building 810
Denver
CO
80225
1-888-275-8747
sciencebase@usgs.gov
Downloadable Data
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
The data set will be available on the USGS ScienceBase web site; http://dx.doi.org/10.5066/F78P5XKP
20200827
William M Perry
U.S. Geological Survey, PACIFIC REGION
IT Specialist
mailing address
800 Business Park Drive
Dixon
CA
95620
530-669-5067
707-678-5039
wmperry@usgs.gov
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998